The present invention relates to the cleaning and drying of thin disks such as glass substrates, flat panel displays, patterned or unpatterned semiconductor substrates and the like. More specifically, the present invention relates to an improved spin-rinse-dryer for rinsing and drying semiconductor substrates.
As semiconductor device geometries continue to decrease, the importance of ultra clean processing increases. Aqueous cleaning within a tank of fluid (or a bath) followed by a rinsing process (e.g., by submersing the substrate in rinsing fluid, or by spraying the substrate with rinsing fluid) achieves desirable cleanliness levels. However, after rinsing is complete, absent use of a drying apparatus, the rinsing fluid would evaporate from the substrate""s surface causing streaking, spotting and/or leaving bath residue on the surface of the substrate. Such streaking, spotting and residue can cause subsequent device failure. Accordingly, much attention has been directed to improved methods for drying a substrate after a final rinsing step.
In addition to providing streak-free drying, such methods should be capable of quickly drying the substrate so as to increase throughput, and should not present a bottleneck for the overall substrate processing system.
Accordingly, a need exists for a method and apparatus that quickly and reliably rinses and dries a substrate such as a semiconductor substrate.
The present invention provides an improved spin-rinse-drier (SRD) comprising a substrate support for holding and rotating a vertically oriented substrate; a source of fluid adapted to supply fluid preferably to both surfaces of a substrate positioned on the substrate support; and, in a first aspect, at least a first shield designed to remove rinsing fluid from the vicinity of the substrate, and particularly to remove rinsing fluid from areas which may allow droplets to fall onto a substrate positioned therebelow. Accordingly, in the first aspect the shield is positioned to receive fluid displaced from a substrate rotating on the substrate support, and is adapted to reflect the received fluid away from the substrate. In a second aspect, a shield is positioned to receive fluid displaced from a substrate rotating on the substrate support, and comprises a hydrophilic substrate facing surface. The entire substrate facing surface of the shield may be hydrophilic, or a hydrophilic wafer facing surface may be mounted (e.g., in the region above the substrate) to a non-hydrophilic shield. In a third aspect, the inventive SRD comprises a shield system having a plurality of vertically and horizontally staggered shields positioned to receive fluid displaced from a substrate rotating on the substrate support, and adapted to carry fluid away from the area above the substrate. As used herein, a shield or shield system described as vertically staggered, or as having various elevations and slopes, refers to the upper region of the shield. It will be understood that the sides and lower regions of the shield may have other shapes.
Further aspects of the invention comprise various combinations of the aspects described above, and/or may comprise further advantageous features. For example, the inventive SRD may have a pressure gradient applied to induce laminar airflow across the surface of the substrate to enhance drying. The plurality of shields can be positioned to further direct the airflow toward the substrate, and may have close vertical spacing such that the airflow enhances the movement of fluid along the shields in a desired direction. The lid of the inventive SRD may be hydrophilic (to enhance fluid sheeting rather than droplet formation) and/or may be sloped to encourage fluid flow in a desired direction. Yet further aspects comprise a sensor and flag adapted to sense a desired position of the flywheel, comprise applying rinsing fluid to the substrate while rotating the substrate at a speed of at least 400 revolutions per minute, comprise a plurality of openable grippers that are biased to a closed position, and have remote pins adapted to selectively open the grippers, grippers that have a hole or slot located at a point of contact between the gripper and a substrate and/or comprise radiused grippers preferably radiused in a plurality of directions.
Other features and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiments, the appended claims and the accompanying drawings.